The present invention relates to an impact bar built into an automobile door and method of manufacture.
Recently, in order to protect the driver and passenger from a side-on collision of an automobile, a pipe-shaped impact bar is incorporated into a side door. A conventional impact bar is generally made up of a steel round pipe. As shown in FIG. 5, the impact bar 20 is assembled in a space between an inner panel 23 and an outer panel 24 by welding and fixing press-formed mounting members 21, 22 to both ends of the impact bar 20, as shown in FIG. 4. The mounting members 21, 22 are fixed to a door frame (not shown) or the like. In this space, the impact bar 20 is adhered and supported by a gumdrop 25 applied to the inner surface of the outer panel 24.
Lately, consumers have demanded higher safety in side-on collisions. In order to meet this need, the strength of the side impact bar must be further enhanced. In the conventional impact bar, however, the strength is determined by the wall thickness of the round pipe. Accordingly, the thickness of the impact bar must be increased to obtain a higher strength, which results in an increased weight of the impact bar.
Thus, it is an object of this invention to provide an impact bar having an enhanced strength against an external force from a radial direction while suppressing any weight increase.